Did you get anything like what you mentioned to work?
I had this very same idea, but I can't find any documentation on accessing
the list of instantiated resources from a template.
On Monday, January 10, 2011 11:01:17 AM UTC, Nick wrote:
>
> Puppet's template() function has the potential to be a rather excellent
> way to
> generate configuration files, so I wondered if it would be able to generate
> something non-trivial, like a set of Shorewall configuration files.
>
> I should note, I have seen the Shorewall example from the puppet "patterns"
> pages, and others based on it [1]. These work by generating lots of
> fragments
> of files in /var/lib/puppet/modules/shorewall, with names prefixed by some
> index
> number, and finally sorting and concatenating them together, interleaved
> with
> various headers and footers. This isn't ideal when, like the zones file,
> there
> can be sections defined in some hierarchy. It also seems to be extremely
> slow
> to run (at least for me - it takes long enough to make some tea *and*
> drink it).
>
> But having tried to implement a version which uses a template (in
> v0.25.4), I
> can't see a way to do it without resorting to some variation of file
> concatenation, because the structure of resources defined in a puppet
> manifest
> is not fully exposed to the templates (that I can see).
>
>
> What I would like to do in general, for example, is to define some
> resources in
> a class like this:
>
> define somesystem::section {
> # This is a placeholder, it doesn't do anything
> # besides represent a section in the generated config file
> }
>
> define somesystem::item($name) {
> # ditto
> }
>
> class somesystem::defaults {
> # this could define any default configuration data, e.g.:
>
> section {"common":
> item {"base": name => "/etc/somesystem"}
> }
> }
>
>
> node "mynode" {
>
> class somesystem::my_config inherits somesystem::defaults {
> # This can extend (or override) the default config data
>
> section {"animals":
> item {"dog": name => 'fido'};
> item {"cat": name => 'fluffy'};
> }
>
> section {"vegetables":
> item {"potato": name => 'spud'};
> }
> }
> }
>
> Then, using a template like this example:
>
> <config> <!-- boilerplate -->
>
> <%# (note that the resources would ideally be iterated
> in the order they appear in the manifest, by default) %>
>
> <% scope.class.resources('section').each do |section| -%>
> <Section id="<%= section.title %>">
> <% section.resources('item').each do |item| -%>
> <item type="<%= item.title %>"><%= item.name %></item>
> <% end -%>
> </Section>
> <% end %>
>
> </config>
>
> ...we might generate something like this:
>
> <config> <!-- boilerplate -->
>
> <Section id="common">
> <item type="base">/var/somesystem</item>
> </Section>
>
> <Section id="animals">
> <item type="dog">fido</item>
> <item type="cat">fluffy</item>
> </Section>
>
> <Section id="vegetables">
> <item type="dog">fido</item>
> <item type="cat">fluffy</item>
> </Section>
>
> </config>
>
> I would guess there is a way to access the manifest's syntax tree from
> within
> the template via the .scope method, but it doesn't seem to be fully
> supported or
> encouraged. [4]
>
> On the other hand, if Puppet had some sort of DOM accessible to templates,
> this
> could be made to work, and Puppet would have a very general and powerful
> way to
> generate all sorts of content from resources defined in manifests.
>
> I'd like to ask:
>
> - Does this seem a worthy and achievable aim in general?
> - Is there some way I could achieve this now, preferably in 0.25.x?
>
> I would guess that the only way is to write a Provider, or to somehow
> implement
> a (client-side?) ERB template which uses the YAML in
> /var/lib/puppet/state/localconfig.yaml as context, neither of which I know
> how
> to do currently. Advice and pointers would be very welcome.
>
> Thanks,
>
> Nick
>
>
> 1. These shorewall modules all seem to be essentially the same:
>
> http://projects.puppetlabs.com/projects/puppet/wiki/Aqueos_Shorewall_Patterns
> https://github.com/camptocamp/puppet-shorewall
> git://labs.riseup.net/module_shorewall
>
> 2. The above depend on this, or something equivalent:
> git://git.black.co.at/module-common
>
> 3. "plugins loaded into memory on the server (e.g., functions) do not
> correctly work in environments [on 0.25.x]"
>
> http://groups.google.com/group/puppet-dev/browse_thread/thread/d39e2db23a7f65b8
>
> 4. A similar idea to mine is discussed here:
> http://www.mail-archive.com/[email protected]/msg06883.html
>
>
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